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Know Your Genes

Cancer Risks: Breast and Ovarian


  • Breast cancer affects 1 in 8 women in the United States. Hereditary breast cancer accounts for approximately 5-10% of these cancers. Most cases of breast cancer are sporadic.


  • Ovarian cancer affects 1 in 70 women. Hereditary ovarian cancer accounts for 10-15% of these cancers. Most cases of ovarian cancer are sporadic.


  • A large proportion of hereditary breast and ovarian cancers can be linked to mutations in the BRCA genes.


BRCA Genes


  • We have about 10,000-20,000 genes in every cell of our body. We have two copies of each gene; one is inherited from our mother and the other comes from our father.


  • When a gene has a mistake in it, it will not work properly and cannot do its job. We call a mistake in the genes a mutation.


  • BRCA1 and BRCA2 are two genes. They both have the same “job” — to stop our bodies from allowing cancer to grow. If someone has a mutation in either BRCA gene, he or she is at a higher-than-average risk to develop cancer. Individuals with a mutation are commonly referred to as “BRCA carriers.”


  • In the general population, between 1 in 500 and 1 in 800 individuals carries a mutation in his or her BRCA1 or BRCA2 gene. 


BRCA and Ashkenazi Jews


There are 3 known common BRCA mutations in the Ashkenazi Jewish population. Individuals of Ashkenazi Jewish descent have a 1 in 40 (or 2.5%) chance of carrying one of these BRCA "founder" mutations. Ashkenazi Jews have a higher-than-average risk to be BRCA carriers. An Ashkenazi Jewish woman who has already had breast cancer has a 1 in 10 chance to be a BRCA carrier.


How one identifies with their religion does not define their ancestry. An individual does not need to practice Judaism to be considered Jewish. If an individual has at least one Ashkenazi Jewish grandparent, that person is at risk of being a carrier for a Jewish genetic disease. Sephardic/Mizrachi individuals face different genetic health issues and are encouraged to speak with a genetic counselor to address their concerns.


BRCA Testing


Genetic testing for mutation in the BRCA genes can uncover carrier status, which can help inform one's medical management and be beneficial in guiding other family members.


The decision of whether or not to pursue genetic testing is always personal and a variety of factors must be taken into consideration. Meeting with a genetic counselor can help you decide if testing is right for you.



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